Vascular access devices are used for communicating fluid with the anatomy of a patient. For example, vascular access devices, such as catheters, are commonly used for infusing fluid, such as saline solution, various medicaments, and/or total parenteral nutrition, into a patient, withdrawing blood from a patient, and/or monitoring various parameters of the patient's vascular system.
A variety of clinical circumstances necessitate that fluid be injected intravenously into a patient by a specialized “power injector” pump intravenously at very high flow rates. The power injector pump may establish a bolus, or small plug of fluid, in the bloodstream of the patient. In some circumstances, a high contrast media is used as the infusant in order produce a bolus that can be imaged via imaging techniques. Power injection procedures generate high pressures within the infusion system, thereby requiring some specialized vascular access devices, extension sets, media transfer sets, pump syringes, and bulk or pre-filled contrast media syringes. A current trend in healthcare is to increase the fluid density of the infusant.
Intravenous infusion rates may be defined as either routine, generally up to 999 cubic centimeters per hour (cc/hr), or rapid, generally between about 999 cc/hr and 90,000 cc/hr (1.5 liters per minute) or higher. For some diagnostic procedures utilizing viscous contrast media, an injection rate of about 1 to 20 ml/second is needed to ensure sufficient bolus concentration. Power injections of viscous media at this injection rate produce significant back pressure within the infusion system that commonly results in a failure of the infusion system components.
FIG. 1 depicts a prior art Luer connector 240 that forms part of a connection that can fail during power injector procedures. The Luer connector 240 forms a connection with a coupler 30 as part of an infusion system that introduces fluid through an extension set 26 across this connection and into an extension tube 38 leading to a catheter adapter or other such device. The Luer connector 240 may include wings 242 and/or rounded protrusions 244 for assisting a user to grip and twist the Luer port 240. The proximal end of the Luer connector 240 includes a Luer connector fitting 72 with Luer threads 74 that interlock with corresponding threads 254 within the coupler 30.
As illustrated in FIGS. 1 to 3, the prior art Luer connector 240 may fail if used improperly. FIG. 1 depicts the relative proportions of the Luer port an index finger 260 (that is approximately 0.75 inches across) of an adult hand. As can be seen, the index finger 260 is substantially larger than the Luer connector 240 even when considering the wings 242 of the Luer port. The length 55 of the Luer connector 240 is less than or equal to about 0.8 inches, the thickness 62 is less than or equal to about 0.17, and the maximum span 246 of the wings is less than or equal to about 0.34 inches. As can be seen, the length 56 of the grippable portion of the body of the Luer connector 240 is less than the length of the entire Luer port 240, since the Luer connector fitting 72 cannot be gripped during operation since it will be covered by the coupler 30. The coupler 30 has a length 250 and a representative depth 252, which represents the optimal depth of the Luer connector fitting 72 when it is fully interlocked within the coupler 30.
FIG. 2 illustrates one problem that can occur during the set-up of the luer connector 240. As depicted, the luer connector 240 may be gripped between an index finger 260 and a thumb 262 of a user. As shown, the luer connector 240 is gripped in a manner that allows a user twisting leverage, with the fingers 260, 262 on the grippable portion of luer port 240 and winds 242. One of the challenges with this luer connector 240 is shown in FIG. 3, wherein when the coupler 30 is advanced over the luer connector fitting 72 and interlocked thereon the user's fingers 260, 262 get in the way and contact the coupler 30 at one or more points 270. At this instance, the user can naturally assume that the coupler 30 and the luer connector 240 are sufficiently interlocked. This assumption may be strengthened by the fact that the resistance to turning can increase proportionally as the luer connector 240 is advanced into coupler 30. This increased resistance combined with the coupler contacting the user's fingers 260, 262 can trigger the user to believe that the connection is secured. The increasing resistance also places pressure on the user's fingers which may feel pain when twisting against the hard material of the connector. However, as shown, in many instances, the luer connector 240 must be advanced an additional distance 256 before it is fully secured to the coupler 30. This final advancement can be difficult and even painful to the user's fingers. In high pressure injection systems, an incomplete connection, such as that shown in FIG. 3 can result in results in a failure of the infusion system or complications, including leaking, a decrease in pressure, disconnection, and contamination.
Additionally, problems may occur when the power injector is programmed to infuse fluids at rates that are too higher for the system components. During power injection procedures, a high-pressure injector is programmed with a maximum flow rate in order to maintain the infusion rate under this maximum value. This maximum limit protects the patient as well as vascular access devices, such as catheter adapters, connected to the power injector. Many, if not all, vascular access devices used in power injection procedures are manufactured to withstand flow rates up to a maximum value. This maximum value is generally included in the vascular access device's published and/or marketing literature, and often provides different maximum values based on the temperature of the infusant. For example, some catheter assemblies are manufactured to infuse a room temperature infusant at a rate of 4 mL/s and a warmed infusant (warmed to the patient's body temperature) at a rate of 6 mL/s. A clinician who programs the maximum flow rates into the power injector system must be aware of the maximum values so that he does correctly programs the power injector. In some past instances, clinicians have not been aware of these values and problems have occurred.